1. Field of the Invention
The present invention relates to a four way, two position, mechanically interlock air valve and more particularly to such a valve adapted in response to pilot air signals to shift its piston position and thereby to selectively provide air pressure to shift the range section of a vehicle transmission at such times as the main section of the transmission is in neutral and which shifting air pressure assists in sealing the valve.
2. Description of the Prior Art
U.S. Pat. No. 3,229,551 to Stuckey discloses a shifting mechanism including an interlock valve, as does U.S. Pat. Nos. 3,393,586 to Zundel; 4,445,393 to Braun, 4,448,094 to Yarnell and 4,550,627 to Lauer et al. However none of these patents disclose a separate locking pin corresponding to each of the main shift rails of the transmission to lock the valve spool in position when one of the main shift rails is moved out of a neutral position. Additionally the valve spool of the present invention has a valve slide retained in the valve spool and such does not appear to be disclosed in the prior art.